Angie Petty missed out by three hundredths of a second in making it to the semi-finals of the 800m after finishing fourth in the third of six heats.

Competing at her third World Championships and requiring to finish in the first three or the next six fastest times Petty clocked 2:01.76.

Petty was in a qualifying position until the last heat, where seven of the runners finished in faster times than the Cantabrian.

The national champion for the last six years and gold medallist at the 2015 World University Games in a personal best 1:59.06 said she was disappointed with her performance.

"I should have been running way better than that 2:01. But it was the way it was run maybe I didnt position myself really well. I hung on Caster (Semenya) on the first lap, I thought I would go past her but then I might die but when I saw it was only sixty at the bell then I was like well I probably shouldve done.

"I go through in 58 fine, but then I didnt seem to have it in that last 100m it just felt a weird race I just didnt get going properly but I still gave it everything in the last 100m but it just didnt feel like I was as sharp as I was hoping," said Petty.

The 25 year old from Christchurch is coached by Danny Mackey in the States.

Semenya won Pettys heat in 2:01.33.

- This story has been automatically published using a media release from Athletics New Zealand